Shelf Life Prediction of Longan with Intermediate Moisture Using Osmotic Dehydration, Combined with Different Packaging and Storage Temperatures

This study aimed to evaluate the shelf life of intermediate moisture longan (IML). A hurdle technology approach was applied, combining osmotic dehydration (OD), hot-air drying, and packaging methods: aluminum foil-laminated plastic bags with nitrogen flushing (Al bag with nitrogen), aluminum foil-laminated plastic bags without nitrogen (the Al bag without nitrogen), and clear plastic bags. Samples were stored at 4, 25, 35, and 45 °C for 24 weeks (six months). The combination of these preservation techniques was effective in extending the shelf life of IML products. Quality changes in IML during storage were significantly influenced by packaging type, storage temperature, and storage duration (<i>p</i> ≤ 0.05). Products stored in all three types of packaging at low temperatures retained better color (L* 31.92 ± 0.97-32.67 ± 1.47) and higher sensory scores (6.5 ± 1.4-6.6 ± 1.5) compared to those stored at higher temperatures (L* 19.54 ± 1.00-20.90 ± 1.48, 3.3 ± 1.6-4.1 ± 1.7). Accelerated shelf life testing using the Arrhenius equation was applied to predict changes in color and sensory acceptance. The kinetics of these quality changes followed the first-order reaction models. Among the packaging types, IML stored in Al bags with nitrogen exhibited the lowest rate constants, indicating slower quality deterioration and better protection compared to Al bags without nitrogen and clear plastic bags. The predictive model demonstrated strong agreement with the experimental data, accurately predicting shelf life at 25 °C and above. However, the model projected a potential shelf life of up to 58 weeks for IML samples packaged in aluminum bags with nitrogen and stored at 4 °C; this projection extended beyond the 24-week experimental period, which still verified a minimum shelf life of 24 weeks. This technology reduces post-harvest food loss, advances packaging innovation for agro-industry, and strengthens food security.